Melt adhesive based on polyamide from branched chain diamine

ABSTRACT

A polyamide copolymer, useful as a melt adhesive especially for textiles, produced from the following monomers 
     1. An unbranched aliphatic dicarboxylic acid with 6-20 C-atoms; 
     2. A diamine mixture consisting of 
     (a) 20-80 mol percent, unbranched aliphatic diamines with 6-20 C-atoms; and 
     (b) 80-20 mol percent branched aliphatic and/or cycloaliphatic diamines; 
     said copolymer having a molecular weight of 2000-40000.

This is a continuation, application Ser. No. 655,044, pending filed Feb.4, 1976, which is a continuation of application Ser. No. 503,538, filedSept. 5, 1974, now abandoned.

BACKGROUND

This invention relates to certain polyamide copolymers prepared fromunbranched aliphatic dicarboxylic acids and a diamine mixture. Moreparticularly, this invention relates to such polyamide copolymers whichare useful as melt adhesives, especially for textiles.

It is known that certain polyamides can be applied as melt adhesives fortextiles. The use of a polyamide for this purpose requires a goodwashing resistance to warm washing suds and a special meltingcharacteristic that allows for processing in a technical importanttemperature range of about 120°-160° C.

It is also known that the melting behavior of a polyamide can beadjusted by copolymerization.

A further demand for textile melt adhesives is a high water absorptionso that the vapor diffusion is not affected in the glued materials.

Up to the present, all polyamides, which have been used as textile meltadhesives, have shown, when in powder form, a tendency to bake or fusetogether, especially when they contain aminocarboxylic acids. Therefore,additives are regularly mixed to these powders in order to improve thetrickling ability. If the aminocarboxylic acids are omitted at meanaverage molecular weight (Mn), the fusion is decreased, but the range ofmelting temperatures is so small, that the polyamide cannot be processedin the common machines.

There is a need to transfer the good effect realized by use of brancheddiamines to compounds free of amino acid.

SUMMARY

The present invention provides polyamides of certain composition and aspecial range of molecular weight which polyamides in powder form do notfuse together, but show all advantages of the suitable polyamides knownas melt adhesives.

The present invention thus relates to a polyamide copolymer ofunbranched, aliphatic dicarboxylic acids with 6 to 20 C-atoms and adiamine mixture consisting of

(a) 20-80 mol percent, preferably 20-70 mol percent unbranched aliphaticdiamines with 6-20, preferably 6-12 C-atoms and

(b) 80-20 mol percent, preferably 80-30 mol percent, branched, aliphaticand/or cycloaliphatic diamines

with a molecular weight of 2000-40000, preferably 6000-25000, as meltadhesive, especially for textile materials.

DESCRIPTION

Smaller quantities of aminocarbonic acids and their lactames can also beused, in this case, however, the molar ratio of dicarboxylic acid:aminocarboxylic acid may not fall below>9:1.

For preparing copolyamides unbranched aliphatic dicarboxylic acids with6-20 C-atoms, as adipic-, pimelic-, suberic-, azelaic- and sebacic acidas well as undecane-, dodecane-, octadecanedicarbonic acid and othersare suitable.

If desired, it is also possible to use smaller quantities of others thanunbranched dicarbonic acids in order to control the melting viscosity.

As suitable unbranched aliphatic diamines with 6-20, preferably 6-12C-atoms, hexamethylene-, heptamethylene-, octamethylene-,nonamethylene-, decamethylene-, undecamethylene-, dodecamethylenediamine and others can be mentioned for example.

As branched aliphatic and cycloaliphatic diamines the followingcompounds with 3-15 C-atoms can be mentioned especially for example:1,2-propylene diamine, 2-and 3-methylhexamethylene diamines,3-isopropyl-hexamethylene diamine, 2-tert, butyl-hexamethylene diamine,2,3-, 2,4-, 2,5-, 3,3- and 3,4-dimethylhexamethylene diamine,3-isooctyl-hexamethylene diamine, 3-iso-dodecylhexamethylene diamine,2-methyl-4-ethylhexylmethyl diamine, 2,2,4- and2,4,4-trimethylhexamethylene diamine, 2,2,5,5-tetramethylhexamethylenediamine, 2,4-diethyl-octamethylene diamine and others as well as thecycloaliphatic diamines, like 3,6-diamino-2-methylcyclohexane,3-aminomethyl-3,5,5-trimethylcyclohexylamine,4,4'-bis-aminomethyl-2,2'-dimethyl-dicyclohexylmethane and the like.Thereby especially those diamines which have 3 alkyl radicals, arepreferred as the 1:1 mixture of 2,2,4- and 2,4,4-trimethylhexylenediamine and the 3-aminomethyl-3,5,5-trimethylcyclohexylamine. Naturally,also mixtures of these compounds can be applied. Advantageously arethose which contain as well aliphatic as cycloaliphatic diamines.

As suitable aminocarboxylic acids and their lactams especially thosewith 4-12 C-atoms are to mention, as the ε-aminobutane-,ε-aminocaproic-, ε-aminododecane acid (ε-aminolaurine acid) and others.

It is preferred to manufacture the copolyamides by prior art methods,whereby the starting materials are heated from 150°-250° C. until thedesired molecular weight is reached. This takes in general 2-5 hours,whereby the reaction time depends on the magnitude of the condensation.In known manner the molecular weights can be adjusted by using a slightexcess of diamine- or dicarboxylic acid or by adding monofunctionalamines or car acids.

The advantages of the copolyamides with respect to their use as meltadhesives, especially for textiles, is shown by the examples.

The use of mono- and dibranched diamines of the invention results in adecrease of the baking.

The subject of the present invention is illustrated by the followingexamples. In order to show the applicability of the manufacturedcopolyamides, a so-called baking-test is performed, which test isdescribed follows.

Baking test

In a cylindrical form of 5 cm interior diameter a tablet of the testingmaterial is pressed at a pressure of 0.12 kg/cm². The form is divided inthe plain into two parts, which forms with the axis of the cylinder anangle of 90°. Both parts of the form are pulled apart in a testingmachine in radial direction. The necessary power is related to thecross-section of the tablet and serves for the estimation of the bakingof the material.

EXAMPLE 1

A polyamide of 1.0 mol adipic acid, 0.4 mol hexamethylene diamine, 0.3mol 3-aminomethyl-3,5,5-trimethylcyclohexylamine (IPD), 0.3 mol of a 1:1mixture of 2,4,4- and 2,2,4-trimethylhexamethylene diamine (TMD) and0.03 mol caprolactam is produced by melt condensation according to knownmethods (5 hours at from 150° to 250° C. increasing temperature). Themolecular weight was approximately 8000. The melt flow index had a valueof approximately 12 at 160° C. and under a load of 2.16 kg. The productwas reduced to a granular size of 80-200 μ and was subjected to a bakingtest. Thereby a value of 44 g/cm² was measured.

If the caprolactam part in the above mentioned composition is increasedto 0.2 mol, the value of the baking goes up to 90 g/cm².

EXAMPLE 2

A polyamide of 1.0 mol adipic acid, 0.2 mol dodecamethylene diamine and0.8 mol TMD was produced by melting condensation according to example 1.The molecular weight was approximately 10000. The melting index at 160°C. and a load of 2.16 kg was 7. Reduced to a granular size of 80-200 μthe product showed at the baking test a value of 38 g/cm².

EXAMPLE 3

A polyamide of 1.0 mol adipic acid, 0.2 mol dodecamethylene diamine and0.8 mol 3-methylhexamethylene diamine was produced by melt condensationaccording to example 1. The molecular weight was approximately 10000.The melt flow index at 160° C. and under a load of 2.16 kg was 10.

Reduced to a granular size of 8-200 μ, the product showed at the bakingtest a value of 60 g/cm².

EXAMPLE 4

A copolyamide of 1.0 mol azelaic acid, 0.6 mol hexamethylene diamine,0.2 mol IPD and 0.2 mol TMD was produced according to example 1. Themolecular weight was approximately 12000. At 160° C. and a load of 2.15kg the melt flow index was 8. The value of the baking test measured at apowder of the granular size of 80-200 μ, was 30 g/cm².

EXAMPLE 5

A copolyamide of 0.8 mol dodecane dicarbonic acid (1,12), 0.2 molazelaic acid, 0.7 mol hexamethylene diamine, 0.15 mol IPD and 0.15 molTMD was produced according to example 1 and mixed with 10 weight percentN-methylbenzene sulfonamide. The molecular weight was approximately18000. At the pulverized material the following values were measured:

    ______________________________________                                        granular size          80-200 μ                                            melt flow index at                                                            160° C. and a load                                                     of 2.16 kg             13                                                     baking test            42 g/cm.sup.2                                          ______________________________________                                    

EXAMPLE 6

A copolyamide of 0.8 mol octadecanediacid-(1.18), 0.2 mol adipic acid,0.7 mol 1.18-diaminooctadecane, 0.15 mol 3.3-dimethylpentanediamine-(1.5) and 0.15 mol 1-methyl-3,6-diaminocyclohexane was producedaccording to example 1. The molecular weight was approximately 12000. Ithad a melting index of 11 at 160° C. and a load of 2.16 kg. The value ofthe baking test, measured at a powder of the granular size of 80-200 μ,was 64 g/cm².

The datas mentioned in the foregoing examples can be conformed by smallmodifications of the composition also to other demands. Therefore theydo not mean a limitation. The molecular weights were stabilied in commonmanner.

What is claimed is:
 1. A hot melt adhesive polyamide copolymerconsisting essentially of the polymeric condensation product of adipicacid and a diamine mixture consisting of 20-80 mol percent ofdodecamethylene diamine and 80-20 mol percent of a mixture of2,2,4-trimethylhexamethylene diamine and 2,4,4-trimethylhexamethylenediamine.
 2. A hot melt adhesive polyamide copolymer consistingessentially of the polymeric condensation product of adipic acid and adiamine mixture consisting of 20-80 mol percent dodecamethylenediamineand 80-20 mol percent 3-methylhexamethylene diamine.
 3. A hot meltadhesive polyamide copolymer consisting essentially of the polymericcondensation product of azelaic acid and a diamine mixture consisting of20-80 mol percent hexamethylene diamine and 80-20 mol percent of amixture of 2,4,4-trimethylhexamethylene diamine,2,2,4-trimethylhexamethylene diamine and3-aminomethyl-3,5,5-trimethylcyclohexylamine.
 4. A hot melt adhesivepolyamide copolymer consisting essentially of the polymeric condensationproduct of dodecane dicarboxylic acid and azelaic acid and a diaminemixture consisting of 20-80 mol percent of hexamethylene diamine and80-20 mol percent of a mixture of3-aminomethyl-3,5,5-trimethylcyclohexylamine,2,4,4-trimethylhexamethylene diamine and 2,2,4-trimethylhexamethylenediamine.
 5. A hot melt adhesive polyamide copolymer consistingessentially of the polymeric condensation product of octadecanediacidand adipic acid and a diamine mixture consisting of 20-80 mol percentdiaminooctadecane and 80-20 mol percent of a mixture of3,3-dimethylpentane diamine and 1-methyl-3,6-diaminocyclohexane.